What Causes Blue Discoloration On Body In The Afternoons?

i need help for my daughter, she 12 and her hands and lips turn blue every afternoon. On occasion her neck, legs, and tops of her feet turn blue as well. She has had a hemoglobin test, ANA, ECHO, and venous blood gas. All have come back normal. She has no other symptoms (ie feeling cold, shortness of breath, aches/pains ect. ) She has had a round of prednisone - no change. She is now on a steroid inhaler and allergy pill ( makes no changes). Also she was given an albuterol inhaler, if she is blue and takes it the blueness subsides for only about 30 min. Then it s back if not worse. Please help